| 摘要 |
PURPOSE:To lead a pickup to a tracking servo system stably by reducing the movement speed of the pickup while the pickup moves from some point between recording tracks to the center of one recording track. CONSTITUTION:After a tracking error signal D is passed through an LPF18, zero-cross detection 19 is performed to generate a detection signal E. The detection signal E is generated synchronously when spot light 1 crosses the nearly center point of a recording track and when it crosses a point between recording tracks. A comparision output C generated when an envelope signal B of a carrier has a constant value and more and the detection signal E are inputted to a timing control circuit 20 to generate a control signal F for the control of a selection switch 14. In an area where servocontrol increases the relative speed between the tracks and pickup, phase characteristics of a servo loop are inverted through the selection of the selection switch 14 to decrease the relative speed. |
